During life, individuals have their eyes cumulatively exposed to harmful light (UV, blue light). Solar lenses protect the eyes from the harmful effects of natural light but a prolonged wearing might in particular affect the optimal regulation of circadian rhythms. Besides, sunglasses are not systematically worn outdoors, particularly in the winter, fall and spring and thus no photo-protection is provided during that time.
There is a need to provide an optical filter, other than a sunglass, that filters a maximum of the potentially harmful wavelengths while (i) ensuring a proper regulation of circadian rhythms, (ii) maintaining visual comfort, in particular for color discrimination and scotopic vision, and (iii) providing an acceptable aesthetics, for any user profile and for a permanent wear.
Existing passive filters can partially modulate the spectrum of light received by the eye. All these solutions have drawbacks:
First, the residual color (due to the filter in the visible range) is constant, and can be very pronounced for strong levels of filtering and/or broad rejected spectral ranges. For example, with a high level of blue-violet light filtering, the residual color is yellow and can significantly degrade the aesthetics of the filter lens, making it less comfortable for the wearer.
Secondly, the filter being passive, the spectral filtering functions cannot be activated at the most appropriate times. For a convenient photo-synchronization of circadian rhythms, filtering is required only for limited periods, at specific hours, and depends on the user's profile (shift workers, teenagers . . . ).
Therefore, an object of the present invention is to provide an optical filter that does not present the above identified drawbacks.
In particular there is a need for active and selective band stop filters in any range of optical wavelengths (UV, visible, IR . . . ).